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AR# 5106

2.1i Floorplanner - PROHIBIT constraints are not supported.


Keywords: Prohibit, Floorplanner, 1.5i, 2.1i, 3.1i

Urgency: Standard

General Description: Prohibit Constraints placed in the UCF file
will be ignored by the 2.1i Floorplanner. In the Floorplanner, this
allows logic to be placed in prohibited areas. Currently it is
the responsibility of the user to not place logic in prohibited
locations within the Floorplanner.

When the design is implemented using the floorplan files,
the PROHIBIT constraints in the UCF file are ignored. If
the IOB locations are not specified in the floorplan and
the design is re-implemented using the floorplan file, IOBs
could be placed in locations that are listed as prohibited
in the UCF file.



In version 3.1i, the user can use the Floorplan -> Prohibit
constraint to prohibit locations in the floorplan for the
design. Alternatively, the user can read in the constraints
from the UCF file using the File -> Read Constraints command
from within the Floorplanner. This will annotate any placement
constraints in the UCF file to the Floorplan (including PROHIBIT


Another way to get around this problem is to manually move
the IOB locations that may be in prohibited areas to
non-prohibited areas in the Floorplanner. Saving this
floorplan will preserve the IOB locations.


To resolve this issue, the design can be run without the
floorplan file (so that the PROHIBIT constraints are not
ignored). The design can then be brought in to the
Floorplanner and the Floorplan -> Replace All With
Placement option will ensure that the IOBs are
placed in non-prohibited locations. The user can
then remove/adjust logic as desired and save the
floorplan. By using this technique, the IOBs will be
locked to locations that are not prohibited in the
floorplan file.


Another possible workaround to this issue is to manually
edit the <design>.mfp file. This is the file that is produced
by the Flooplanner when the floorplan is saved. To do this:

1. Floorplan the desired logic and save the floorplan
2. Open the <design>.mfp file in a text editor
3. Add the PROHIBIT constraints to the end of the .mfp
file with the following syntax (for example to prohibit P10):
4. Run the tools as usual through the design flow

NOTE : This method is recommended only if no other
method will resolve the issue. It is not recommended for
the user to manually edit the .mfp file as a part of the
normal design flow.
AR# 5106
Date Created 08/31/2007
Last Updated 07/09/2001
Status Archive